Methods and systems for fabrication of shaped fiber elements for scanning fiber displays

ABSTRACT

A fiber optic element of a fiber scanning system includes a motion actuator having longitudinal side members, an internal orifice, a first support region, a central region, and a second support region. The fiber optic element also includes a first fiber optic cable passing through the internal orifice and having a first fiber joint as well as a second fiber optic cable passing through the internal orifice. The second fiber optic cable has a second fiber joint disposed in the central region and spliced to the first fiber joint, a second coupling region, a light delivery region, and a light emission tip. The light delivery region is characterized by a first diameter and the light emission tip is characterized by a second diameter less than the first diameter.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/286,498 filed on Feb. 26, 2019, now U.S. Pat. No. 10,845,543, issuedon Nov. 24, 2020, entitled “METHODS AND SYSTEMS FOR FABRICATION OFSHAPED FIBER ELEMENTS FOR SCANNING FIBER DISPLAYS,” which is acontinuation of U.S. patent application Ser. No. 15/851,005 filed onDec. 21, 2017, now U.S. Pat. No. 10,254,483 issued on Apr. 9, 2019,entitled “SHAPED FIBER ELEMENTS FOR SCANNING FIBER DISPLAYS,” whichclaims the benefit of and priority to U.S. Provisional PatentApplication No. 62/438,380 filed on Dec. 22, 2016, entitled “METHODS ANDSYSTEMS FOR FABRICATION OF SHAPED FIBER ELEMENTS FOR SCANNING FIBERDISPLAYS,” the disclosures of which are hereby incorporated by referencein their entirety for all purposes.

This application incorporates by reference in their entirety each of thefollowing U.S. patent applications: U.S. patent application Ser. No.15/851,049 filed on Dec. 21, 2017, now U.S. Pat. No. 10,723,653 issuedon Jul. 28, 2020, entitled “METHODS AND SYSTEMS FOR FABRICATION OFSHAPED FIBER ELEMENTS USING LASER ABLATION;” and U.S. patent applicationSer. No. 15/851,317 filed on Dec. 21, 2017, now U.S. Pat. No. 10,437,048issued on Oct. 8, 2019, entitled “METHODS AND SYSTEMS FOR MULTI-ELEMENTLINKAGE FOR FIBER SCANNING DISPLAY.”

BACKGROUND OF THE INVENTION

Modern computing and display technologies have facilitated thedevelopment of systems for so called “virtual reality” or “augmentedreality” experiences, wherein digitally reproduced images or portionsthereof are presented to a viewer in a manner wherein they seem to be,or may be perceived as, real. A virtual reality, or “VR,” scenariotypically involves presentation of digital or virtual image informationwithout transparency to other actual real-world visual input; anaugmented reality, or “AR,” scenario typically involves presentation ofdigital or virtual image information as an augmentation to visualizationof the actual world around the viewer.

Despite the progress made in these display technologies, there is a needin the art for improved methods and systems related to augmented realitysystems, particularly, display systems.

SUMMARY OF THE INVENTION

The present invention relates generally to methods and systems forfabrication of shaped fiber optic cables. More particularly, embodimentsof the present invention provide methods and systems for fabricatingfibers with tapered and other predetermined profiles. The invention isapplicable to a variety of applications in computer vision and imagedisplay systems.

According to an embodiment of the present invention, a fiber opticelement of a fiber scanning system is provided. The fiber optic scanningsystem can include multiple fiber optic elements. The fiber opticelement includes a motion actuator (e.g., a piezoelectric actuator)having longitudinal side members, an internal orifice disposed betweenthe longitudinal side members, a support region disposed at one end ofthe motion actuator, and a projection region opposing the supportregion. The longitudinal side members can include a first piezoelectricelement operable to contract/expand and a second piezoelectric elementoperable to expand/contract in opposition to the first piezoelectricelement. The internal orifice is characterized in some embodiments by acylindrical profile defined by an internal diameter. In this embodiment,the coupling region can be substantially cylindrical and defined by anouter diameter substantially equal to the internal diameter.

The fiber optic elements also includes a fiber optic cable passingthrough the internal orifice. The fiber optic cable has a couplingregion disposed between the longitudinal side members and in mechanicalcontact with the projection region, a light delivery region extendingaway from the projection region of the motion actuator, and a lightemission tip. The fiber optic element can also include an interfacelayer (e.g., glass frit or epoxy) disposed between the coupling regionand the projection region. The light delivery region is characterized bya first diameter and the light emission tip is characterized by a seconddiameter less than the first diameter. In an embodiment, the lightdelivery region is characterized by a reentrant profile extendingbetween the projection region of the motion actuator. As an example, thefiber optic cable can be tapered from the light deliver region to thelight emission tip. The fiber scanning system can be an element of afiber scanning projection display.

In an embodiment, the coupling region can include a support portion inmechanical contact with the longitudinal side members and a flexureregion disposed between the support region and the projection region.The flexure region is separated from the longitudinal side members by aflexure distance. In this embodiment, the coupling region furtherincludes a second support portion in mechanical contact with thelongitudinal side members. The second support portion can be disposed inthe support region.

According to another embodiment of the present invention, a fiber opticelement of a fiber scanning system is provided. The fiber optic elementincludes a motion actuator having longitudinal side members, an internalorifice disposed between the longitudinal side members, a first supportregion disposed at one end of the motion actuator, a central region, anda second support region disposed at an opposing end of the motionactuator. A first fiber optic cable passes through the internal orifice.The first fiber optic cable has a first coupling region disposed betweenthe longitudinal side members and a first fiber joint disposed in thecentral region. A second fiber optic cable passes through the internalorifice. The second fiber optic cable has a second fiber joint disposedin the central region and spliced to the first fiber joint and a secondcoupling region disposed between the longitudinal side members and inmechanical contact with the second support region. The fiber opticelements also includes a light delivery region extending away from thesecond support region of the motion actuator and a light emission tip.the light delivery region is characterized by a first diameter and thelight emission tip is characterized by a second diameter less than thefirst diameter.

According to a specific embodiment of the present invention, a fiberoptic element of a fiber scanning system is provided. The fiber opticelement includes a motion actuator having longitudinal side members, aninternal orifice disposed between the longitudinal side members, a firstsupport region disposed at one end of the motion actuator, a centralregion, and a second support region disposed at an opposing end of themotion actuator. The fiber optic element also includes a retainingelement disposed in the first support region and a first opticalwaveguide passing through the retaining element and the internalorifice. The first optical waveguide has a first mating joint disposedin the retaining element. The fiber optic element further includes asecond optical waveguide passing through the internal orifice. Thesecond optical waveguide has a second mating joint disposed in theretaining element and joined to the first mating joint and a secondcoupling region disposed between the longitudinal side members and inmechanical contact with the second support region. The fiber opticelements additionally includes a light delivery region extending awayfrom the second support region of the motion actuator and a lightemission tip. The light delivery region is characterized by a firstdiameter and the light emission tip is characterized by a seconddiameter less than the first diameter.

According to another specific embodiment of the present invention, amethod of fabricating a shaped fiber is provided. The method includesproviding a fiber optic cable, covering a portion of the fiber opticcable with an etch jacket to define an exposed region of the fiber opticcable and a covered region of the fiber optic cable, and exposing theexposed region of the fiber optic cable and the etch jacket to anetchant solution. The method also includes removing at least a portionof the exposed region of the fiber optic cable in response to exposureto the etchant solution and wicking the etchant solution under the etchjacket to remove at least a portion of the covered region of the fiberoptic cable. Wicking the etchant solution under the etch jacket caninclude capillary flow of the etchant solution.

According to a particular embodiment of the present invention, a fiberactuator mechanism is provided. The fiber actuator includes a motionactuator having longitudinal side members, an internal orifice disposedbetween the longitudinal side members, a support region disposed at oneend of the motion actuator, and a projection region opposing the supportregion and having a projection face. The fiber actuator also includes afiber optic cable passing through the internal orifice. The fiber opticcable has a coupling region disposed between the longitudinal sidemembers and in mechanical contact with the projection region and a lightdelivery region extending away from the projection region of the motionactuator. The light delivery region includes a flange extending alongthe projection face of the projection region. The fiber optic cablefurther includes a light emission tip. The light delivery region canfurther include a tapered region extending longitudinally away from theprojection face of the projection region. As an example, a slopeassociated with the tapered region decreases with distance from theflange.

According to an embodiment of the present invention, a fiber actuatormechanism is provided. The fiber actuator mechanism includes a motionactuator having longitudinal side members, an internal orifice disposedbetween the longitudinal side members, a support region disposed at oneend of the motion actuator, and a projection region opposing the supportregion and having a projection face and a projection exterior surface.The fiber actuator mechanism also includes a fiber optic cable passingthrough the internal orifice. The fiber optic cable has a couplingregion disposed between the longitudinal side members and in mechanicalcontact with the projection region and a light delivery regionsurrounding and extending away from the projection region of the motionactuator. The light delivery region includes a first region parallel tothe projection face and a second region parallel to the projectionexterior surface. The fiber actuator mechanism further includes a lightemission tip. The first region can be in mechanical contact with theprojection face. In an embodiment, the second region is in mechanicalcontact with the projection exterior surface. Moreover, the lightdelivery region can further include a third region surrounding theprojection region.

According to another embodiment of the present invention, a method offabricating a shaped fiber is provided. The method includes providing afiber optic cable having a support region and an emission region,providing an etch solution (e.g., including hydrofluoric acid), andcoating at least a portion of the emission with an etch resistant mask.The method further includes inserting the support region into the etchsolution, etching a central portion of the support region, and removingthe coating on the emission region. Etching the central portion of thesupport region can result in the formation of a flexure region. Themethod also includes inserting the emission region into the etchsolution and etching the emission region. Etching the emission regioncan include withdrawing the emission region from the etch solution at adecreasing rate (e.g., a nonlinear rate) as a function of time. The etchsystem can also include an inert solution (e.g., isooctane) adjacent theetchant solution, for example, floating on the etchant solution. Themethod can also include coating the etched central portion beforeetching the emission region.

According to a specific embodiment of the present invention, a method offabricating an etched fiber waveguide is provided. The method includesproviding an etchant system including an etchant solution (e.g.including HF), inserting a first end of a fiber optic cable into theetchant solution, and withdrawing the first end of the fiber optic cableat a first rate. The first rate can vary (e.g., decrease) as a functionof time in a linear or nonlinear manner. The method also includesinserting a second end of the fiber optic cable opposing the first endinto the etchant solution and withdrawing the second end of the fiberoptic cable at a second rate. The second rate can vary (e.g., decrease)as a function of time in a linear or nonlinear manner. The etch systemcan also include an inert solution (e.g., isooctane) adjacent theetchant solution, for example, floating on the etchant solution. In someembodiments, a central portion of the fiber optic cable disposed betweenthe first end and the second end is not etched.

According to another specific embodiment of the present invention, amethod of fabricating a shaped fiber is provided. The method includesproviding a fiber optic cable having a support region and an emissionregion and providing an etch solution including a first inert layer, anetch layer adjacent the first inert layer, and a second inert layeradjacent the etch layer. The method also includes coating at least aportion of the emission region with an etch resistant mask, insertingthe support region into the etch layer, and etching a central portion ofthe support region to form a flexure region disposed between sections ofthe support region and characterized by a thinner diameter than thesections of the support region. The method further includes removing thecoating on at least a portion of the emission region, inserting theemission region into the etch layer, and etching the emission region toform a tapered profile. The first inert layer can include isooctane andthe etch layer can include HF acid. The second inert layer can includean oil with a density higher than a density of an etchant in the etchlayer.

According to a particular embodiment of the present invention, a methodof fabricating a tapered fiber emission tip is provided. The methodincludes providing a fiber optic cable having an emission region,providing an etch solution including an inert layer and an etch layer.and inserting the emission region through the inert layer into the etchlayer. The method also includes etching a portion of the emissionregion, introducing agitation between the emission region and the etchsolution, and withdrawing the emission region from the etch layer. Insome embodiments, introducing agitation includes both agitation of theetch solution and agitation of the fiber optic cable. Withdrawing theemission region from the etch layer can be characterized by anincreasing rate as a function of time.

According to another particular embodiment of the present invention, amethod of fabricating a tapered fiber emission tip is provided. Themethod includes providing a fiber optic cable having an emission region,providing an etch solution including an inert layer and an etch layerand inserting the emission region through the inert layer to a firstdepth in the etch layer. The method also includes etching a portion ofthe emission region, at least partially withdrawing the emission regionfrom the etch layer, and re-inserting the emission region through theinert layer to a subsequent depth in the etch layer less than the firstdepth. The method further includes repeating at least partiallywithdrawing the emission region and re-inserting the emission region andcompletely withdrawing the emission region from the etch layer. Thesubsequent depth can be gradually decreased during the repeatingprocess.

According to an embodiment of the present invention, a method offabricating a tapered fiber emission tip is provided. The methodincludes providing a fiber optic cable having an emission region and anemission face, coating the emission region with an etch resistant mask,and exposing a portion of the emission region adjacent the emission faceto form a sidewall mask and an emission face mask. The method alsoincludes providing an etch solution, inserting the emission region intothe etch solution, and etching a portion of the emission region to formsuccessively deeper etch profiles. The method further includesdetermining an etch endpoint and removing the emission region from theetch solution. Determining an etch endpoint can include detectingseparation between the emission face and the emission face mask.

According to a particular embodiment of the present invention, a methodof fabricating a lens on an optical fiber tip is provided. The methodincludes providing a fiber optic cable having an emission region and anemission face, providing an etch solution having a surface, andpositioning the emission face to make contact with the surface of theetch solution. The method also includes forming a meniscus of the etchsolution surrounding the emission region. The meniscus is characterizedby a greater width adjacent the emission face and an initial height.

The method further includes etching the emission region to form aninitial etch profile, decreasing the height of the meniscus, and etchingthe emission region to form a subsequent etch profile. Etching theemission region to form the subsequent etch profile can be aself-limiting process.

According to a specific embodiment of the present invention, a waveguidefabrication system is provided. The waveguide fabrication systemincludes a robot, an etch system coupled to the robot, and a cleaningsystem coupled to the robot. The waveguide fabrication system alsoincludes a mask formation system coupled to the robot, a mask removalsystem coupled to the robot, and a computer coupled to the robot. Thewaveguide fabrication system can further include an input/output stackcoupled to the robot.

Numerous benefits are achieved by way of the present invention overconventional techniques. For example, embodiments of the presentinvention provide methods and systems that can be used to fabricatefibers that can be integrated into fiber scanning display systems. Theseand other embodiments of the invention along with many of its advantagesand features are described in more detail in conjunction with the textbelow and attached figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a simplified side view illustrating a shaped fiber of a fiberscanning system according to an embodiment of the present invention.

FIG. 1B is a simplified side view illustrating a shaped fiber includinga flexure region according to an embodiment of the present invention.

FIG. 1C is a simplified side view illustrating a shaped fiber includinga support region according to an embodiment of the present invention.

FIG. 1D is a simplified side view illustrating a multi-element shapedfiber according to an embodiment of the present invention.

FIG. 1E is a simplified side view illustrating a multi-element shapedfiber according to another embodiment of the present invention.

FIG. 1F is a simplified perspective view of a piezoelectric motionactuator according to an embodiment of the present invention.

FIG. 1G is a simplified end view illustrating a multi-element motionactuator according to an embodiment of the present invention.

FIG. 2A is a simplified side view illustrating a shaped fiber includinga reentrant profile according to an embodiment of the present invention.

FIG. 2B is a simplified side view illustrating a shaped fiber includingan optical element at the tip of the fiber according to an embodiment ofthe present invention.

FIG. 3A is a simplified side view illustrating a portion of an opticalwaveguide and an etch resistant jacket according to an embodiment of thepresent invention.

FIG. 3B is a simplified side view illustrating wicking of an etchantbelow the etch resistant jacket illustrated in FIG. 3A according to anembodiment of the present invention.

FIG. 3C is a simplified side view illustrating further wicking of theetchant below the etch resistant jacket.

FIG. 3D is a simplified side view illustrating tapering of the opticalwaveguide according to an embodiment of the present invention.

FIG. 3E is a simplified flowchart illustrating a method of fabricating ashaped fiber according to an embodiment of the present invention.

FIG. 4 is a simplified side view illustrating a shaped fiber including asupport flange according to an embodiment of the present invention.

FIG. 5A is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to an embodiment of thepresent invention.

FIG. 5B is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to another embodiment of thepresent invention.

FIG. 5C is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to yet another embodiment ofthe present invention.

FIG. 6A is a simplified flowchart illustrating a method of fabricating ashaped fiber according to an embodiment of the present invention.

FIG. 6B illustrates an etch system according to an embodiment of thepresent invention.

FIG. 6C illustrates an etch system according to an alternativeembodiment of the present invention.

FIG. 6D is a simplified flowchart illustrating a method of fabricatingan etched fiber waveguide according to an embodiment of the presentinvention.

FIG. 6E illustrates an etch system according to a particular embodimentof the present invention.

FIG. 7 is a simplified flowchart illustrating a method of fabricating atapered fiber emission tip according to an embodiment of the presentinvention.

FIG. 8 is a simplified flowchart illustrating a method of fabricating atapered fiber emission tip according to another embodiment of thepresent invention.

FIG. 9 is a simplified flowchart illustrating a method of fabricating ashaped fiber using an etch process according to an embodiment of thepresent invention.

FIGS. 10A-10D are simplified side views illustrating processing of afiber in accordance with the method provided in relation to FIG. 9.

FIG. 10E is a simplified perspective view illustrating a fiber with aprotective cover according to an embodiment of the present invention.

FIGS. 11A-11C are simplified side views illustrating a method offabricating a shaped fiber tip according to an embodiment of the presentinvention.

FIG. 12 is a simplified schematic diagram illustrating a waveguidefabrication system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Embodiments of the present invention relate to methods and systems forfabricating elements for fiber scanning display systems. In some fiberscanner systems, the diameter of the fiber optic cable is significantlynarrower than the inner diameter of the piezoelectric actuator thatholds the fiber. In these systems, a bonding material is utilized tofill the resulting gap. As an example, an epoxy can be used to join thefiber to the piezoelectric actuator. Since the stiffness of epoxy canvary with temperature, the epoxy joint can impact fiber performance.Moreover, adhesion problems can degrade fiber performance.

FIG. 1A is a simplified side view illustrating a shaped fiber of a fiberscanning system according to an embodiment of the present invention.Referring to FIG. 1A, the motion actuator utilizes a piezoelectricstructure or actuator and actuation of the piezoelectric structure isillustrated by a first longitudinal side member 110 expanding ordistending as illustrated by arrows 112 while a second longitudinal sidemember 120 opposing the first longitudinal side member 110 iscontracting as illustrated by arrows 122. As series of opposingexpansion and contraction motions will oscillate the tapered fiber 130in the plane of the figure. The tapered fiber tapers from a width ofabout 200-250 μm at the right end of the motion actuator to a width ofabout 20 μm-40 μm at the fiber tip 132, also referred to as a lightemission tip.

The fiber optic element illustrated in FIG. 1A can be part of a fiberscanning projection display system. The fiber optic element includes amotion actuator including opposing longitudinal side members 112 and122. As the opposing longitudinal side members contract/expand, thefiber optic cable passing between the longitudinal side membersoscillates in the plane of the figure. Although a single fiber isillustrated in FIG. 1A and other figures herein, the scope of thepresent invention includes multi-core fiber systems in which multiplefiber cores are utilized in a scanning display system. One of ordinaryskill in the art would recognize many variations, modifications, andalternatives.

In the embodiment illustrated in FIG. 1A, the motion actuator 105includes an internal orifice 107 disposed between the longitudinal sidemembers 112 and 122. The motion actuator can be defined such that asupport region 108 is disposed at one end (e.g., the left end) of themotion actuator and a projection region 109 is disposed at opposing end(e.g. the right end) of the motion actuator opposite to the supportregion.

A fiber optic cable 130 passes through the internal orifice 107. Thefiber optic cable 130 has a coupling region 131 disposed between thelongitudinal side members and in mechanical contact with the projectionregion 109. In the embodiment illustrated in FIG. 1A, the internalorifice of the motion actuator is characterized by a cylindrical profiledefined by an internal diameter and the fiber optic cable 130 has acoupling region 131 that is substantially cylindrical and defined by anouter diameter substantially equal to the internal diameter of themotion actuator. The fiber optic cable, as a result, completely fillsthe motion actuator barrel to provide a rugged mechanical connection andcan be a press-fit member in some embodiments. In the embodimentillustrated in FIG. 1A, the materials of the motion actuator, i.e., thepiezoelectric material, and the fiber optic cable, e.g., glass, are indirect mechanical contact because of the substantially matched sizes.

FIG. 1F is a simplified perspective view of a piezoelectric motionactuator according to an embodiment of the present invention. Thepiezoelectric motion actuator illustrated in FIG. 1F includes fouractuation inputs (+X, −X, +Y, and −Y) disposed in a cylindrical casing.The fiber optic cable passes through the orifice 107 and by actuation ofthe four actuation inputs, the fiber optic cable can be scanned in twodimensions. In FIG. 1F, contraction of the +X actuation input andexpansion of the −X actuation input causes the piezoelectric motionactuator to tilt toward the +X axis. Although the motion illustrated inFIG. 1F is in two dimensions (i.e., along planes defined by the x-axisand y-axis), embodiments of the can also expand or contract all fouractuation inputs in unison to contract/expand along the z-axis. Thus,embodiments of the present invention provide for both motion in thex-direction and the y-direction, as well as the use of cylindricalactuators that compress/expand in the z-direction.

In addition to the cylindrical motion actuator illustrated in FIG. 1A,the scope of the present invention includes implementations in whichother geometries are utilized for the motion actuator. As an example, inan embodiment, the motion actuator includes a plurality of opposingmotion actuation elements (e.g., piezoelectric elements) that operate inconjunction with each other as a multi-element motion actuator. FIG. 1Gis a simplified end view illustrating a multi-element motion actuatoraccording to an embodiment of the present invention. The viewillustrated in FIG. 1G is aligned with the longitudinal axis. Asillustrated in FIG. 1G, a first motion actuation element 192 positionedon one side of the fiber optic cable 193 and a second motion actuationelement 194 positioned on the opposite side of the fiber optic cable cancontract/expand in concert to cause the fiber optic cable to move in thehorizontal plane. A third motion actuation element 196 positioned on athird side of the fiber optic cable 193 and a fourth motion actuationelement 198 positioned on the opposite side of the fiber optic cable cancontract/expand in concert to cause the fiber optic cable to move in thevertical plane. By actuation of all four motion actuation elements, thefiber can be scanned in two dimensions as appropriate to use in aprojection display. The embodiment illustrated in FIG. 1G can providefor a lighter system by reducing the piezoelectric mass. In addition tothe rectangular geometry illustrated in FIG. 1G, other geometries,including hexagonal, triangular, and the like are included within thescope of the present invention.

In some embodiments, the materials of the motion actuator, e.g., thepiezoelectric material, and the fiber optic cable, e.g., glass, are indirect mechanical contact. In other embodiments, substantial mechanicalcontact is provided by the insertion of an interface layer between themotion actuator and the fiber optic cable. In these embodiments, thefiber optic cable is slightly smaller in diameter than the motionactuator barrel, enabling a thin layer of adhesive to be utilized tojoin the fiber optic cable to the motion actuator. In these embodiments,substantial mechanical contact is provided by the insertion of theinterface layer between the motion actuator and the fiber optic cable.The interface layer can be disposed between the coupling region 131 andthe projection region 109 as well as at other portions of the motionactuator. As examples, the interface layer can include at least one offrit glass, epoxy, or the like. In one embodiments, frit glass, forexample, in the form of a preform, is placed at the interface betweenthe motion actuator and the fiber, for example, to the right of the endof the motion actuator. The frit glass, which can have different layersmaking up the preform, can then be reflowed into the interface betweenthe coupling region and the projection region. After reflowing the fritglass may be present both in the interface and outside the motionactuator, forming a seal around the fiber where it exits the motionactuator. As an example, a ring of material could be placed around thefiber at the right side of the motion actuator. Upon heating, thematerial could flow into the interface region and form a stress reliefelement surrounding the fiber. When used as an interface material, epoxyis a damping material, which can provide benefits in someimplementations.

The fiber optic cable includes a light delivery region 136 that extendsaway from the projection region 109 of the motion actuator 105 and alight emission region 138.

The fiber optic cable also includes a light emission tip 134. The fiberis tapered in some embodiments such that the light delivery region 136is characterized by a first diameter and the light emission tip 134 ischaracterized by a second diameter that is less than the first diameteras the fiber tapers towards the tip. The tapering can be continuous(i.e., constantly decreasing diameter as a function of position) in someembodiments.

The tapering in the light delivery region 136 can be rapid, with thetapering decreasing in rate as it approaches the tip. Thus, the slope ofthe taper can be large in the light delivery region and smaller in thelight emission region. As an example, the starting diameter of the fibercan be in the range of 200 μm-250 μm, the rapid tapering can reduce thediameter to a value in the range of 100 μm-125 μm within about 50 μm to100 μm, for example, 85 μm of fiber length, and then the taperingprofile can be reduced to a substantially linear taper to a diameter atthe light emission tip 134 of 20 μm-40 μm, for example, 30 μm, 35 μm, orthe like. The rapid tapering in the light delivery region can providestrain and/or stress relief and, as a result, the tapering profile inthis region can be selected to reduce or minimize strain on the fiberduring actuation and reduce stress localization. Elliptical profiles,other arcs, including non-linear profiles determined using finiteelement analysis, and the like can be utilized for the tapering profile.

FIG. 1B is a simplified side view illustrating a shaped fiber includinga flexure region according to an embodiment of the present invention.Referring to FIG. 1B, in order to reduce potential binding between thelongitudinal side members and the fiber optic cable as the cableoscillates in response to actuation of the motion actuator, a flexureregion is provided between the support region and the projection region.The spatial separation between the fiber optic cable and thelongitudinal side members allows the fiber optic cable to move in thelateral direction, reducing or eliminating binding as the longitudinalside members expand and contract. The lateral direction covers allmotion in the plane orthogonal to the longitudinal direction. As anexample, if the longitudinal direction is aligned with the z-axis,lateral motion will include motion in the x-y plane. Thus, lateralmotion includes spiral motion in which the fiber optic cable moves inthe x-y plane as the center of the fiber traces out a spiral pattern inthe x-y plane.

Referring to FIG. 1B, to reduce the stiffness of the motion actuator andimprove flexibility, the coupling region of the fiber optic cableincludes a support portion 140 in mechanical contact with thelongitudinal side members and a flexure region 142 disposed between thesupport region and the projection region, wherein the flexure region isseparated from the longitudinal side members by a flexure distance, d.The flexure region formed by necking down the fiber diameter enablesadditional flexibility in comparison with designs that increase themechanical contact between the fiber optic cable and the interiorsurfaces of the longitudinal support members.

FIG. 1C is a simplified side view illustrating a shaped fiber includinga support region according to an embodiment of the present invention. InFIG. 1C, the fiber optic cable also includes a coupling region 150, notonly at the projection region of the motion actuator, but also at thesupport region of the motion actuator. In this embodiment, the lateraldimension of the fiber optic cable is decreased in the flexure region142 to reduce binding, but increased adjacent the support region and theprojection region in order to provide the desired mechanical contactbetween the motion actuator and the fiber optic cable. The couplingregion 150 can be referred to as a second support portion in mechanicalcontact with the longitudinal side members. In an embodiment, the fiberdiameter can be increased back to the original diameter to match theinner diameter of the longitudinal side members of the motion actuator.

FIG. 1D is a simplified side view illustrating a multi-element shapedfiber according to an embodiment of the present invention. Referring toFIG. 1D, in some embodiments, multiple types of optical waveguides areutilized to assemble the fiber scanning system. As discussed below inrelation to FIG. 1E, the second fiber optic cable 162 illustrated inFIG. 1D can be replaced with an optical waveguide element fabricated bymechanisms other than drawn fiber processes.

For purposes of clarity, the discussion related to FIG. 1D will discussthe use of a fiber optic cable as the second optical waveguide, butembodiments of the present invention are not limited to thisimplementation. In addition, although embodiments of the presentinvention are discussed herein in relation to the use of a fiber opticcable, other optical waveguide structures can be utilized in place offiber optic cables. In addition to optical waveguide structures,integrated optical elements and the like can be spliced to fiber opticcables or other optical structures and motion actuators using thetechniques described herein. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

As illustrated in FIG. 1D, a first fiber optic cable 161 can be utilizedas an input fiber 161 and a second fiber optic cable 162 can be utilizedas a delivery fiber that is mechanically coupled to the motion actuatorand includes a tapered light delivery region. The input fiber can be asmaller diameter fiber than the delivery fiber. The two fiber opticcables are spliced at a splice joint 160. In the illustrated embodiment,the splice joint 160 is positioned in the flexure region so that alateral separation (e.g., a flexure distance) is provided between thesplice joint and the longitudinal side members.

Referring to FIG. 1D, the fiber optic element, which can be part of afiber scanning system, includes a motion actuator, a first fiber opticcable, and a second fiber optic cable. The motion actuator includeslongitudinal side members, an internal orifice disposed between thelongitudinal side members, a first support region disposed at one end ofthe motion actuator, a central region, and a second support regiondisposed at an opposing end of the motion actuator.

The first fiber optic cable 161 passes through the internal orifice ofthe motion actuator and has a first coupling region 140 disposed betweenthe longitudinal side members and a first fiber joint (the left side ofsplice joint 160) disposed in the central region. A second fiber opticcable passing through the internal orifice and has a second fiber joint(the right side of splice joint 160) disposed in the central region andspliced to the first fiber joint. In some embodiments, the second fiberoptic cable also has a second coupling region disposed between thelongitudinal side members and in mechanical contact with the secondsupport region.

Referring to the embodiment illustrated in FIG. 1D, the second fiberoptic cable 162 can include a light delivery region extending away fromthe second support region of the motion actuator and a light emissiontip. The light delivery region can be tapered towards the light emissiontip. In some embodiments, the diameter of the second fiber optic cablein first coupling region 140 is substantially equal to the innerdiameter of the internal orifice of the motion actuator. In otherembodiments, a mechanical fixture can be used to retain the firstcoupling region of the first fiber optic cable with respect to the firstsupport region. As an example, an o-ring can be used to support the thinfiber between the longitudinal side members.

Although not illustrated in FIG. 1D, the first coupling region of thefirst fiber optic cable can be in mechanical contact with the firstsupport region of the motion actuator as illustrated by coupling region150 in FIG. 1C. Thus, combinations of the elements illustrated in thevarious figures provided herein can be combined as appropriate to theparticular application. One of ordinary skill in the art would recognizemany variations, modifications, and alternatives.

Methods of fabricating the second fiber optic cable can include maskingand etching processes. As an example, a fiber optic cable could bemasked with an etch resistant mask on the portions that will become thetip of the fiber. After the tip is masked, the central region can beimmersed in an etchant solution, for example, the three-layer etchsystem illustrated in FIG. 6C. As the tip of the fiber passes throughthe etchant during the immersion process, the mask would protect the tipfrom being etched. After the central region is etched to form a reduceddiameter flexure region and the fiber is removed from the etch system,the etch resistant mask on the tip can be removed and a second etchingprocess can be used to form the desired shape (e.g., a tapered shape)for the tip of the fiber. Additionally, during this second etchingprocess, an etch resistant mask can be applied to the central region topreserve the shape formed after the first etch process.

In some embodiments, the order can be modified, for example, reversed,to form the tip first and then the central region as the flexure region.In these processes, the rate at which the fiber is inserted and/orwithdrawn from the etchant can be utilized to control the shape of thefiber. One of ordinary skill in the art would recognize many variations,modifications, and alternatives.

FIG. 1E is a simplified side view illustrating a multi-element shapedfiber according to another embodiment of the present invention. In thisimplementation, the motion actuator is attached to a mechanical mountusing supports 170, which can also be referred to as an attachmentcollar. The motion actuator vibrates relative to the base (not shown) towhich supports 170 are attached. In this alternative embodiment, thesplice joint 160 that joins the two fiber optic cables is positionedbetween supports 170 to which the motion actuator is coupled.

As shown in FIG. 1E, a retaining element 172 is disposed in the firstsupport region 108. The first fiber optic cable passes between theretaining element 172 and the internal orifice of the motion actuator.The first fiber optic cable is joined to the second fiber optic cable bythe splice joint 160, which is defined by a first fiber joint of thefirst fiber optic cable (to the left of the splice joint) and a secondfiber joint of the second fiber optic cable (to the right of the splicejoint). The splice joint is positioned longitudinally such that it isdisposed in the retaining element. The position of the splice joint inthe retaining element and between the supports 170 reduces themechanical stress on the splice joint, which is an area of reduced flex,since the motion actuator is moving with respect to the supports.

In some embodiments, the retaining element 172 is formed by depositing aflexible adhesive, for example, a silicone ball, on the splice jointbetween the first optical fiber and the second optical fiber and movingthe sliced fibers with the deposited flexible adhesive such that theadhesive is positioned between the supports and allowing the adhesive tocure in this position. Although silicone is used an example, the presentinvention is not limited to this implementation and other retainingelements that provide suitable mechanical rigidity and desired lifetimecan be utilized.

Moreover, although the splice joint is illustrated between the supportsin FIG. 1E, this is not required by the present invention and the splicejoint can be moved to other positions to the left of the supports, whichcan also be characterized as low-flex regions. Thus, the precision withwhich the splice joint is placed can be relaxed in some embodiments,improving manufacturability.

Referring once again to FIG. 1E, a fiber optic element of a fiberscanning system is provided. The fiber optic element includes a motionactuator, a first optical waveguide, and a second optical waveguide. Thefirst optical waveguide can be a first fiber optic cable and the secondoptical waveguide can be a second fiber optic cable. The motion actuatorhas longitudinal side members and an internal orifice disposed betweenthe longitudinal side members. The motion actuator has a first supportregion 108 disposed at one end of the motion actuator and a secondsupport region 109 disposed at an opposing end of the motion actuator,thereby defining a central region 180.

The motion actuator can include a piezoelectric actuator, which can bepositioned in a plane including the first support region 108, the firstmating surface splice, and the second mating surface. In otherembodiments, the longitudinal side members include piezoelectricelements that contract and expand as discussed above. In theseembodiments, the piezoelectric actuator positioned in the plane of thesplice joint 160 can be replaced with mechanical supports that supportthe motion actuator.

A retaining element 172 is disposed in the first support region 108between the longitudinal side members. A first optical waveguide 181,which can be a first fiber optic cable, passes through the retainingelement and the internal orifice. The first optical waveguide has afirst mating surface (the left side of splice joint 160) disposed in theretaining element 172. The second optical waveguide passes through theinternal orifice and has a second mating surface (the right side ofsplice joint 160) disposed in the retaining element 172 and joined tothe first mating surface. The second optical waveguide, which can be asecond fiber optic cable, has a second coupling region 140 disposedbetween the longitudinal side members and in mechanical contact with thesecond support region 109. The second optical waveguide further includesa light delivery region extending away from the second support region ofthe motion actuator and a light emission tip. The light delivery regioncan be tapered as illustrated in FIG. 1E.

As illustrated in FIG. 1E, the retaining element 172 is operable toretain the splice joint 160 with respect to the first support region 108and support the portions of the first and second optical waveguides.Accordingly, as illustrated in FIG. 1E, mechanical contact between thesecond coupling region 140 and the longitudinal side members as well asbetween the first and second optical waveguides, the retaining element,and the first support region 108 of the motion actuator provides forsecuring of the optical waveguides. At the same time, the flexure regionenables the second optical waveguide to move laterally as the lightemission tip oscillates in the plane of the figure. As shown in FIG. 1E,the second optical waveguide can include a flexure region 142 disposedbetween the second mating surface and the second coupling region 140 toprovide a lateral separation (i.e., a flexure distance) between thelongitudinal side members and the flexure region.

Referring to FIG. 1E, the first optical waveguide can be fabricated as afiber optic cable. In some embodiments, the second optical waveguide isfabricated as a second fiber optic cable, but this is not required byembodiments of the present invention. In alternative embodiments, thesecond optical waveguide can be fabricated using processes other thanfiber drawing processes, for example, using a micro-electro-mechanicalsystem (MEMS) or a micro-opto-electro-mechanical system (MOEMS)microfabrication process. Thus, molded parts and optical waveguidesfabricated using additive manufacturing are included within the scope ofthe present invention, for example, cantilevered structures, channelwaveguides, and the like.

As discussed above in relation to FIG. 1D, the second fiber optic cablecan be replaced with another type of optical waveguide structure.Accordingly, embodiments of the present invention can utilizecombinations of fiber optic cables fabricated using fiber drawingprocesses and optical waveguide elements fabricated using othermicrofabrication techniques. It should be noted that the embodimentsdescribed herein as utilizing fiber optic cables can be modified toutilize other forms of optical waveguide structures in place of or incombination with one or more fiber optic cables. Thus, the embodimentsthat are illustrated as using a fiber optic cable as an element are notlimited to this particular waveguide design and other optical waveguidedesigns can be utilized in these embodiments. One of ordinary skill inthe art would recognize many variations, modifications, andalternatives.

FIG. 2A is a simplified side view illustrating a shaped fiber includinga reentrant profile according to an embodiment of the present invention.In the embodiment illustrated in FIG. 2A, the light delivery region ofthe fiber optic cable is etched or otherwise processed to modify thediameter between the actuators making up the projection region of themotion actuator. As illustrated in FIG. 2A, the light delivery regionincludes a reentrant profile adjacent (e.g., surrounding) the deliverywaveguide. As the fiber oscillates in the plane of the figure inresponse to the motion actuation, the portions of the delivery waveguide205 adjacent the reentrant profile 210 will experience reduced strainsince the edges 220 of the delivery waveguide 205 substantially matchthe contour of the reentrant profile 210 as the edges make contact withthe reentrant profile.

The smooth curved surface characterizing the reentrant profile 210provides a reduced stress contact surface that is beneficial forlifetime. The reentrant profile illustrated in FIG. 2A can be integratedinto other designs discussed herein. Methods of fabricating thereentrant profile are discussed in additional detail with respect toFIGS. 3A-3C. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

Although a tapered fiber with a tapered end is illustrated in FIG. 2A,this is not required by the present invention and the end of the fibercan feature other optical structures. As an example, a lensed elementmay be utilized. FIG. 2B is a simplified side view illustrating a shapedfiber including an optical element at the tip of the fiber according toan embodiment of the present invention. An optical element 230 isintegrated into the tip of the fiber. The optical element can provideone of several optical functions including focusing as a lens,collimating the fiber output, and the like. In some embodiments, inaddition to optical properties, the optical element also serves amechanical function with the mass of the optical element being utilizedto accentuate the oscillatory motion of the cantilevered fiber.

FIG. 3A is a simplified side view illustrating a portion of an opticalwaveguide and an etch resistant jacket according to an embodiment of thepresent invention. As illustrated in FIG. 3A, an optical waveguide 320,which can be an optical fiber, is partially coated with an etchresistant jacket 310. The etch resistant jacket can be formed usingmaterials that are resistant to etching, or the like.

FIG. 3B is a simplified side view illustrating wicking of an etchantbelow the etch resistant jacket illustrated in FIG. 3A according to anembodiment of the present invention. As the optical waveguide 320 andthe etch resistant jacket 310 is exposed to an etchant solution, theexposed portion 322 of the waveguide will be etched as illustrated bythe decrease in diameter D of the waveguide. Additionally, an inclusioncan be formed at the jacket/waveguide interface and capillary actionwill draw etchant between the waveguide (e.g., fiber) and the jacketand, as a result, some of the etchant will wick under the jacket,etching the reentrant profile 324 illustrated in FIG. 3B.

FIG. 3C is a simplified side view illustrating further wicking of theetchant below the etch resistant jacket. As the etch process continues,the diameter of the waveguide in the exposed portion continues todecrease and the reentrant profile is formed at a greater depth underthe jacket. The etch process is continued until the desired reentrantprofile is formed. Using some etch chemistries, such as BOE, a reentrantprofile associated with a diameter reduction on the order of 50 μm canbe accomplished in less than an hour, for example, 20 minutes.

FIG. 3D is a simplified side view illustrating tapering of the opticalwaveguide according to an embodiment of the present invention. Afterformation of the reentrant profile, the tapered profile 340 illustratedin FIG. 3D can be fabricated using additional material removalprocesses. As an example, the original etch resistant jacket could beremoved and/or the fiber could be coated again with an additional etchresistant jacket and a secondary etch process could be used to form thedesired tapered profile.

FIG. 3E is a simplified flowchart illustrating a method of fabricating ashaped fiber according to an embodiment of the present invention. Themethod 350 includes providing a fiber optic cable (360) and covering aportion of the fiber optic cable with an etch jacket to define anexposed region of the fiber optic cable and a covered region of thefiber optic cable (362). The method also includes exposing the exposedregion of the fiber optic cable and the etch jacket to an etchantsolution (364) and removing at least a portion of the exposed region ofthe fiber optic cable in response to exposure to the etchant solution(366). The method further includes wicking the etchant solution underthe etch jacket to remove at least a portion of the covered region ofthe fiber optic cable (368). In an embodiment, wicking the etchantsolution under the etch jacket comprises capillary flow of the etchantsolution. In one implementation, the portion of the covered region ofthe fiber optic cable removed under the etch jacket is characterized bya reentrant profile.

FIG. 4 is a simplified side view illustrating a shaped fiber including asupport flange according to an embodiment of the present invention. Asillustrated in FIG. 4, the motion actuator can be implemented as ahollow piezoelectric tube through which the fiber optic cable passes. Inthis embodiment, the initial diameter of the fiber optic cable (e.g.,the outer cladding diameter) is larger than the interior diameter of themotion actuator. As an example, starting with a 500 μm diameter fiber,the portion to the left of plane 403 is etched to a diametersubstantially equal to the interior diameter of the motion actuator.Thus, a flange 425 is created so that the flange covers the end of themotion actuator. The presence of the flange provides a strong mechanicalcoupling between the motion actuator and the fiber optic cable since thebase region of cantilever extends to the front surface of the actuator.

Referring once again to FIG. 4, a fiber actuator mechanism is providedthat includes a motion actuator and a fiber optic cable passing throughthe motion actuator. The motion actuator 410 has longitudinal sidemembers 412 and 414, an internal orifice 411 disposed between thelongitudinal side members, a support region 416 disposed at one end ofthe motion actuator, and a projection region 418 opposing the supportregion and having a projection face 419.

The fiber optic cable 420 passes through the internal orifice 411 andhas a coupling region disposed between the longitudinal side members andin mechanical contact with the projection region. The fiber optic cablealso has a light delivery region extending away from the projectionregion of the motion actuator. The light delivery region includes aflange 425 extending along the projection face of the projection region.In the illustrated embodiment, the projection face is substantiallyplanar and the flange is substantially planar, providing a tight fitbetween the two surfaces. The fiber optic cable further includes a lightemission tip (not shown in FIG. 4, but illustrated in FIG. 1A).

In an embodiment, the light delivery region of the fiber optic cableincludes a tapered region that extends longitudinally away from theprojection face of the projection region as illustrated in FIG. 4. Thetapered region can be linearly tapered or non-linearly tapered asappropriate to the particular application. In the implementationillustrated in FIG. 4, the slope associated with the tapered regiondecreases with distance from the flange, initially starting at a steeptapering angle and then become less steeply tapered as the distance tothe light emission tip decreases. In other embodiments, the slope isvaried in other manners. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

In embodiments in which the motion actuator utilizes ceramicpiezoelectric materials, the motion actuator is relatively stiff as itvibrates, whereas the fiber is more flexible. Accordingly, at the endsof the vibration range, the fiber exerts pressure on the piezoelectricas the fiber reaches the end of the vibration range. As a result, thetip of the piezoelectric actuator experiences high forces. In order toaddress these forces, some embodiments utilize fiber structures thatpartially surround the piezoelectric actuator.

FIG. 5A is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to an embodiment of thepresent invention. In the implementation illustrated in FIG. 5A, apocket for the ends of the longitudinal side members of the motionactuator (e.g., a piezoelectric actuator) is provided such that thefiber optic cable includes elements that surround portions of the motionactuator. This embodiment prevents the motion actuator elements (e.g.,the ends of the longitudinal side members) from cracking as the fiberoptic cable oscillates in the plane during operation. The structuralintegrity is also increased as the surface area over which the surfacesof the longitudinal side members and the surfaces of the fiber opticcable overlap, increases.

The direct mechanical coupling illustrated in FIG. 5A ensconces the endsof the longitudinal side members in the pockets formed in the fiberoptic cable. The pressure applied by the opposing inner surfaces andouter surfaces of the fiber optic cable prevents cracking of the motionactuator arms.

Referring to FIG. 5A, a fiber actuator mechanism is provided thatincludes a motion actuator and a fiber optic cable. The motion actuatorhas longitudinal side members, an internal orifice disposed between thelongitudinal side members, a support region disposed at one end of themotion actuator, and a projection region opposing the support region.The projection region has a projection internal surface 520 of theinternal orifice, a projection face 522 and a projection exteriorsurface 524.

A fiber optic cable passes through the internal orifice and has acoupling region disposed between the longitudinal side members and inmechanical contact with the projection region, a light delivery regionsurrounding and extending away from the projection region of the motionactuator, and light emission tip. The light delivery region includes afirst region 521 parallel to the projection internal surface 520, asecond region 523 parallel to the projection face 522, and a thirdregion 525 parallel to the projection exterior surface 524. A lightemission tip (not shown) is also an element of the fiber optic cable.

In the embodiment illustrated in FIG. 5A, the first region 521 of thefiber is in mechanical contact with the projection internal surface 520of the motion actuator and the second region 523 is in mechanicalcontact with the projection face 522. In other embodiments, the thirdregion 525 is in mechanical contact with the projection exterior surface524. The light delivery region can further include a fourth region 530surrounding the projection region to provide for additional mechanicalsupport of the fiber and the motion actuator. In FIG. 5A, the contactsurfaces are substantially planar in cross-section, for example,cylindrical, but as described below, this is not required by the presentinvention.

FIG. 5B is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to another embodiment of thepresent invention. In the embodiment illustrated in FIG. 5B, thefabrication process has not formed squared off surfaces, but surfacesthat include curved features. In addition, the ends of the motionactuator can be substantially flat as illustrated in FIG. 5B, but inother embodiments, the ends can be rounded or characterized by othershapes as appropriate to the particular application. In the embodimentillustrated in FIG. 5B, if the width of the longitudinal side members iswider than the width of the pockets, the portions of the fibersurrounding the pockets will flex as the longitudinal side members areinserted into the pockets, providing tight contact between the interiorsurfaces of the pockets and the exterior surfaces of the longitudinalside members.

Depending on the application, the surface contact between the pocketsand the longitudinal side members is provided at sufficient levels toensure sufficient mechanical coupling. For instance, the size (e.g.,length and width) of the contact surfaces is selected in someembodiments to provide mechanical support without the use of adhesives.In other embodiments, additional adhesion materials, including epoxy canbe used to enhance the mechanical coupling, with the curved featuresproviding room for the epoxy to move during assembly. For example, apotting material can be used to counteract the expansion of ceramicmaterials that can be utilized in the motion actuator and provide highhoop stress.

FIG. 5C is a simplified side view illustrating a shaped fiber includinga motion actuator coupling region according to yet another embodiment ofthe present invention. In the embodiment illustrated in FIG. 5C, pocketswith interior surfaces that are substantially planar in cross-sectionare utilized in conjunction with outer surfaces that are rounded.

In order to fabricate the structures illustrated in FIGS. 5A-5C, a laserablation and/or sculpting process can be utilized to form the pocketsinto which the motion actuator elements are inserted. For instance thefiber can be etched to form the portion that will pass through themotion actuator, leaving a large diameter section including fourthregion 530. The exposed surface can then be laser ablated to form thepockets. Another suitable fabrication technique is to mask and etch thedesired structures, for example, in a multi-stage mask and etch process.Combinations of etching and laser ablation can also be used to form therecesses or pockets.

FIG. 6B illustrates an etch system according to an embodiment of thepresent invention. In the embodiment illustrated in FIG. 6B, a sapphireor other etch-resistant container 650 is partially filled with anetchant solution 652 (e.g., an HF-based acid mixture) and an inertsolution 654 (e.g., isooctane). The etchant solution 652 can includevarious components suitable for etching of the optical elementsdescribed herein, including buffered oxide etch (BOE) solution,including a surfactant such as ammonium fluoride, and the like. Theinert solution 654 is less dense than the etchant solution in thisimplementation and prevents evaporation of the etchant and protects theportions of the fiber immersed in the inert solution from being etched,for example, by etchant evaporating and the resulting vapor etching thefiber. The inert layer can be referred to as a float layer in someimplementations.

The portion of the fiber 670 to be etched is inserted into the etchantsolution, for example, passing through the inert solution to enter theetchant solution. As the fiber is withdrawn from the etchant solution ata predetermined rate, the desired profile is etched into the etchedportion of the fiber. In FIG. 6B, the fiber is illustrated as beinginserted in a vertical direction that is perpendicular to the surface ofthe etchant solution. In some embodiments, the angle at which the fiberis inserted and/or withdrawn is controlled, for example, varied as afunction of time, to control the etching profile achieved.

FIG. 6B illustrates camera 656, which can be used to image the fiber 670as portions of the fiber are immersed in etchant solution 652. In theembodiment illustrated in FIG. 6B, the camera 656 is positioned levelwith the interface 653 between the inert solution 654 and the etchantsolution 656. In other embodiments, the camera can be placed above theinterface, below the interface, or the like. In such off-set views, thecamera can observe the fiber without an interfering image of a meniscusline of an etchant or refractive error that may be captured by viewingat an interface of different materials (such as an inert or etchantlayer). In other words, at off-set angles the camera may view the fiberthrough a fewer number of intermediate mediums and calculate an etchrate based on captured images compensating for fewer indices ofrefraction the captured light propagated to arrive at the camera.Additionally, an off-set enables the collection of additional imageinformation. While the level viewing depicted in FIG. 6B permits etchrate viewing as a function of diameter changes, an off-set view maycapture certain circumference etch characteristics as well such as howuniform the etch process is occurring along a fiber exterior, beyondsimply the diameter width according to a particular view. In someembodiments, explained herein in additional detail in relation toagitation of the etch bath, non-uniform etching as determined from anoff-set view may trigger an agitator to change a position of the fiberif non-uniform etching is observed. Additionally, although a singlecamera is illustrated in FIG. 6B, multiple cameras placed in variousorientations with respect to the interface 653 can be utilized byembodiments of the present invention. Using camera 656, a user isenabled to view interface 653 and fiber 670 during insertion andwithdrawal from the etch system. As an example, using one or morecameras, the diameter of the fiber at the interface can be determinedand utilized in controlling the etch process. Accordingly, embodimentsof the present invention utilize one or more cameras, computer visionsystems, and the like to achieve fiber elements with various sectionshaving predetermined lengths and diameters as described herein.

The fiber optic cable can be masked with an etch resistant mask to formmasked regions that will not be etched despite being inserted into theetchant solution. The mask prevents etching of the masked region, forexample, to fabricate the flexure region 142 illustrated in FIG. 1C.Subsequently, the mask can be removed and the fiber optic cablereinserted, with the previously etched flexure region above the etchantsolution, in order to etch the projection region of the fiber opticcable.

The etch system illustrated in FIG. 6B can be utilized to fabricateoptical waveguide structures as illustrated by the second fiber opticcable in FIG. 1D. The end adjacent the fiber splice 160 can be etched byinsertion and withdrawal from the etchant solution at a rate varied toproduce increased etching as the fiber is withdrawn. Subsequently, thelight delivery region 136 and the light emission tip 138 can be etchedto form the desired tapered profile.

FIG. 6A is a simplified flowchart illustrating a method of fabricating ashaped fiber according to an embodiment of the present invention. Themethod illustrated in FIG. 6A utilizes a two-layer etch system asillustrated in FIG. 6B, but this is not required by the presentinvention and other configurations of etch systems can be utilizedaccording to an embodiment of the present invention.

Referring to FIG. 6A, the method includes providing a fiber optic cablehaving a support region and an emission region (610) and providing anetch solution (612). The method also includes coating at least a portionof the emission with an etch resistant mask (614), inserting the supportregion into the etch solution (616), and etching a central portion ofthe support region (618). In an embodiment, the support region of thefiber is substantially the same diameter as the interior diameter of themotion actuator and the central portion of the support region is etchedto form the flexure region while preserving the fiber diameter atportions of the support region that will make mechanical contact withthe motion actuator.

The method further includes removing the coating on the emission region(620), inserting the emission region into the etch solution (622), andetching the emission region (624). In some embodiments, the supportregion is partially or entirely coated with an etch resistant coatingbefore the emission region is etched. Etching of the emission region canform tapered profiles and the like.

Although a fiber optic cable is discussed in relation to FIG. 6A, themethods described herein are applicable to the fabrication of otheroptical waveguide structures and are the present invention is notlimited to the fabrication of shaped fibers formed from fiber opticcables, but can include shaped optical waveguides fabricated fromstarting materials other than optical fibers.

It should be appreciated that the specific steps illustrated in FIG. 6Aprovide a particular method of fabricating a shaped fiber according toan embodiment of the present invention. Other sequences of steps mayalso be performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated in FIG. 6A may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

FIG. 6D is a simplified flowchart illustrating a method of fabricatingan etched fiber waveguide according to an embodiment of the presentinvention. The method 685 includes providing an etchant system includingan etchant solution (690) and inserting a first end of a fiber opticcable into the etchant solution (692). The etchant solution can includeHF acid. The method also includes withdrawing the first end of the fiberoptic cable at a first rate (694). The first rate can vary as a functionof time, for example, decreasing as a function of time to form a taperedstructure that is thicker at the end processed near the end of the etchprocess. The decrease (or increase) in the first rate can be nonlinearor linear.

The method further includes inserting a second end of the fiber opticcable opposing the first end into the etchant solution (696) andwithdrawing the second end of the fiber optic cable at a second rate(698). The second rate can vary as a function of time, for example,decreasing as a function of time. The decrease (or increase) in thesecond rate can be nonlinear or linear.

It should be appreciated that the specific steps illustrated in FIG. 6Dprovide a particular method of fabricating an etched fiber waveguideaccording to an embodiment of the present invention. Other sequences ofsteps may also be performed according to alternative embodiments. Forexample, alternative embodiments of the present invention may performthe steps outlined above in a different order. Moreover, the individualsteps illustrated in FIG. 6D may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

As illustrated in FIG. 6B, the etchant system can include an inertsolution adjacent the etchant solution, for example floating above theetchant solution. In this case, the inert solution is less dense thanthe etchant solution, for example, isooctane as an inert solution for HFas the etchant solution. In some implementations, a central portion ofthe fiber optic cable disposed between the first end and the second endis not etched during the process illustrated in FIG. 6D and the firstend and the second end can have different shaped profiles.

Some embodiments provide a lens on the tip of the fiber. The fibershaping processes described herein can be utilized to form such a lenson fiber tip, for example, by masking the tip of the fiber and formingthe desired shape for the other regions of the fiber. Then the otherregions already completed can be masked, the mask on the tip removed,and the lens can be formed on the tip. In alterative embodiments, theorder is reversed with the lens on the tip formed first and then thesides of the fiber shaped or sculpted subsequently. The lens can befabricated as a hexagon lens or other suitable optical shapes. One ofordinary skill in the art would recognize many variations,modifications, and alternatives.

Referring to the structures shown in FIG. 1E, a benefit of utilizing afirst optical waveguide, which can be a fiber optic cable, and a secondoptical waveguide, is that the second optical waveguide can befabricated using the two-level etch system illustrated in FIG. 6B. Theflexure region 142 of the second optical waveguide can be fabricated byetching in the etch system, preserving the dimensions of the supportportion 140 and not etching the portion of the second optical waveguidethat will become the delivery and emission sections. Subsequently, theright side of the second optical waveguide can be fabricated, forexample, tapered as illustrated using the two-level etch system. Ofcourse, the order could be reversed. After fabrication of the two ends,the second optical waveguide can be spliced to the first opticalwaveguide. Accordingly, this design simplifies the fabrication processin comparison to other techniques.

FIG. 6C illustrates an etch system according to an embodiment of thepresent invention. In the embodiment illustrated in FIG. 6C, athree-layer approach is utilized in which the etch-resistant container650 is partially filled with a first inert material that is denser thanthe etchant solution and forms an inert layer 660, an etchant solution652, and a second inert material that is less dense than the etchantsolution and forms a second inert layer 662. As an example, using anHF-based etchant solution, an oil such as Krytox™ oil can be used as thefirst inert material and isooctane can be used as the second inertmaterial. Using this three-layer etch system, only the portion of thefiber inserted into the etchant solution is etched, enabling structuressimilar to those illustrated in FIG. 1C to be fabricated in which acentral portion of the fiber is etched (e.g., the flexure region) toform a lateral narrowing in the fiber optic cable in comparison with theends surrounding the central portion. In some embodiments, portions ofthe fiber that are not to be etched can be masked off, for example bothends when the central portion is etched to supplement the protectionprovided by the inert layers.

Utilizing the three-layer etch system illustrated in FIG. 6C, a methodof fabricating a shaped fiber can be provided. The method includesproviding a fiber optic cable having a support region and an emissionregion and providing an etch solution. The etch solution includes afirst inert layer, an etch layer adjacent the first inert layer, and asecond inert layer adjacent the etch layer. The method also includescoating at least a portion of the emission region with an etch resistantmask, inserting the support region into the etch layer, and etching acentral portion of the support region to form a flexure region disposedbetween sections of the support region and characterized by a thinnerdiameter than the sections of the support region. The method furtherincludes removing the coating on at least a portion of the emissionregion, inserting the emission region into the etch layer, and etchingthe emission region to form a tapered profile.

The first inert layer can include isooctane and the etch layer caninclude HF acid. The second inert layer can include an inert materialthat is denser than the material in the etch layer. Referring to FIG.1C, the portion of the fiber optic cable to the right of the couplingregion can be masked to prevent etching of these regions during theetching of the flexure region. Similarly, after the flexure region hasbeen etched, this region can be masked as needed while the projectionregion of the fiber optic cable is etched to form the desired taperedprofile. Variations on this process are included within the scope of thepresent invention, including masking of additional regions, removal ofportions of masked regions to facilitate etching, reversal of the orderof processing, and the like.

It should be noted that although fiber optic cables are illustrated asthe waveguide that is etched to form the shaped and/or taperedstructures discussed herein, embodiments of the present invention arenot limited to the etching of fiber optic cables. Other waveguidestructures can be etched and shaped using the techniques describedherein. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

During use of the etch systems described herein, for example, thetwo-layer etch system illustrated in FIG. 6B, the hydrophilic characterof the fiber optic cable results in a meniscus forming at the interfacebetween the etchant and the inert layer. As the fiber is withdrawn fromthe etchant (for example, at an increasing rate as a function of time toform a tapered profile in which the tip is etched more than the lightdelivery region), the etchant solution can thus adhere to the fiber at alevel above the surface of the etchant present at the edges of thecontainer 650. This wicking of the etchant solution in the vicinity ofthe fiber will be supported as the fiber is withdrawn until the heightreaches a point at which the pull of gravity exceeds the surfacetension. At this point, the etchant solution will collapse back down tothe level defined by the surface of the etchant. The additional etchingthat occurs during the time that the meniscus adheres to the fiber canresult in scalloping of the fiber as an overlay on the desired fibershape.

FIG. 6E illustrates an etch system according to a particular embodimentof the present invention. In FIG. 6E, an alternative two-layer etchsystem is illustrated in which a first layer of etchant 604 and a secondlayer of etchant 602 are separated by an inert layer 603. The etchantand inert layers can share similarities with the etchant and inertlayers described above. The etch system illustrated in FIG. 6E can beutilized to form structures similar to the shaped fiber including aflexure region illustrated in FIB 1B. In this example, a shaped fibercould be formed by first inserting the fiber into the bath illustratedin FIG. 6E, thereby etching the ends of the fiber while preserving theoriginal dimensions of the centrally located support portion 140. Afterformation of the flexure region and the initial shaping of the emissionend of the fiber, the fiber can be immersed in an etch system as shownin FIG. 6B to further taper the emission end of the fiber. Thus, using acombination of the etch systems described herein, components can befabricated by the use of vertical insertions into a set of one or morelinearly staged etch systems (e.g., etch baths) as an alternative tomethods in which the fiber optic cable is insert and removed, rotated,and subsequently reinserted. Accordingly, it will be appreciated thatcombinations of the etch systems described herein can be utilized tofabricate components with the desired shapes. One of ordinary skill inthe art would recognize many variations, modifications, andalternatives.

FIG. 7 is a simplified flowchart illustrating a method of fabricating atapered fiber emission tip according to an embodiment of the presentinvention. The method illustrated in FIG. 7 reduces or prevents thescalloping of the sides of the fiber as described above. The method 700of fabricating a tapered fiber emission tip includes providing a fiberoptic cable having an emission region (710) and providing an etchsolution including an inert layer and an etchant (712). The etchant canalso be referred to as an etchant layer. The method also includesinserting the emission region through the inert layer into the etchant(714) and etching a portion of the emission region (716).

In order to prevent undesired scalloping of the sides of the fiber, themethod includes introducing agitation between the emission region andthe etchant (718) as the emission region is withdrawn from the etchant(720). The introduction of agitation can be implemented by agitation ofthe etch system including the etchant and the inert layer. In otherimplementations, introducing agitation can be accomplished by agitationof the fiber optic cable with respect to the etch system. In theseimplementations, the fiber optic cable can be moved laterally tointroduce lateral agitation. The lateral agitation can be random,semi-random, or the like. Such randomization can prevents standing wavesthat could be undesirable. The agitation and the resulting solutionsurface shape can be controlled to provide the desired fiber shape.

In other embodiments, the agitation of the fiber optic cable can beaccomplished by introducing longitudinal agitation of the fiber opticcable. Moreover, in addition to these methods, agitation of the fiberoptic cable can be accomplished by rotation of the fiber optic cable.The various methods described herein can be combined, for example,performing both agitation of the etch system and agitation of the fiberoptic cable, either laterally, longitudinally, or in combination.

Although the method illustrated in FIG. 7 has been discussed in relationto the fabrication of a tapered fiber emission tip, the presentinvention is not limited to this particular structure and is applicableto other portions of the fibers and optical waveguides discussed herein,including the flexure region, which can have a constant diameter over apredetermined longitudinal extent. In this case, reduction in orprevention of scalloping will preserve the desired constant diameter. Itshould be appreciated that the specific steps illustrated in FIG. 7provide a particular method of fabricating a tapered fiber emission tipaccording to an embodiment of the present invention. Other sequences ofsteps may also be performed according to alternative embodiments. Forexample, alternative embodiments of the present invention may performthe steps outlined above in a different order. Moreover, the individualsteps illustrated in FIG. 7 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

FIG. 8 is a simplified flowchart illustrating a method of fabricating atapered fiber emission tip according to another embodiment of thepresent invention. As discussed above, although FIG. 8 is discussed inrelation to the fabrication of a tapered fiber emission tip, the presentinvention is not limited to this particular structure and is applicableto other portions of the fibers and optical waveguides discussed herein,including the flexure region and other regions. In this method, whichprovides an alternative to methods in which the fiber is immersed andwithdrawn from the etchant completely at a predetermined rate, which canvary as a function of time, the fiber is immersed in the etchant to afirst predetermined depth, completely withdrawn, and then re-immersed toa second predetermined depth. The withdrawal process can break themeniscus that forms on the fiber as discussed above.

Referring to FIG. 8, the method 800 of fabricating a tapered fiberemission tip includes providing a fiber optic cable having an emissionregion (810) and providing an etch solution including an inert layer andan etch layer (812). Thus, in this method, the etchant 652 illustratedin FIG. 6 is referred to as an etch layer. The method also includesinserting the emission region through the inert layer to a first depthin the etch layer (814) and etching a portion of the emission region(816). The method further includes at least partially withdrawing theemission region from the etch layer (818) to break the surface tensionof the etchant and re-inserting the emission region through the inertlayer to a subsequent depth in the etch layer less than the first depth(820).

The process of at least partially withdrawing the emission region andre-inserting the emission region is repeated a predetermined number oftimes (822), effectively accomplishing a gradual and complete withdrawalof the emission region from the etch layer (824). In an embodiment, thesubsequent depth is gradually decreased during the repetition of thewithdrawal and re-inserting processes.

It should be appreciated that the specific steps illustrated in FIG. 8provide a particular method of fabricating a tapered fiber emission tipaccording to an embodiment of the present invention. Other sequences ofsteps may also be performed according to alternative embodiments. Forexample, alternative embodiments of the present invention may performthe steps outlined above in a different order. Moreover, the individualsteps illustrated in FIG. 8 may include multiple sub-steps that may beperformed in various sequences as appropriate to the individual step.Furthermore, additional steps may be added or removed depending on theparticular applications. One of ordinary skill in the art wouldrecognize many variations, modifications, and alternatives.

FIG. 9 is a simplified flowchart illustrating a method of fabricating ashaped fiber using an etch process according to an embodiment of thepresent invention. FIGS. 10A-10D are simplified side views illustratingprocessing of a fiber in accordance with the method provided in relationto FIG. 9.

Referring to FIG. 9, the method 900 includes providing a fiber opticcable having an emission region and an emission face (910), coating theemission region with an etch resistant mask (912), and exposing aportion of the emission region adjacent the emission face to formsidewall mask and an emission face mask (914). Referring to FIG. 10A,the fiber optic cable has an emission region 1010 and an emission face1012. The emission region 1010 and the emission face 1012 of the fiberoptic cable are coated with an etch resistant mask 1014. Thus, the maskis illustrated as coating both the end and sides of the fiber. Referringto FIG. 10B, after exposure of a portion of the emission region adjacentthe emission face, the exposed portion is removed to form the sidewallmask 1020 and the emission face mask 1022. The portion of the fiber notcovered by the masks can then be etched as described below.

The spatial separation between the sidewall mask 1020 and the emissionface mask 1022 is illustrated as L in FIG. 10B and can be used tocontrol the shape of the etched profile. For small separations, theetchant is effectively wicked under the masks, whereas for largerseparations, the sides of the fiber are etched significantly. Byselecting the spatial separation, control of the curvature of the fibertip is provided by some embodiments.

The method also includes providing an etch solution (916), inserting theemission region into the etch solution (918), and etching a portion ofthe emission region to form successively deeper etch profiles (920).Referring to FIG. 10C, four subsequent etch profiles 1030, 1032, 1034,and 1036 are illustrated by solid, dashed, dotted, and solid lines,respectively. As the etching process proceeds, the etchant wicks underthe sidewall mask in the process illustrated, extending the etch asillustrated, but this is not required by the present invention. Themethod further includes determining an etch endpoint (922) and removingthe emission region from the etch solution (924). As illustrated in FIG.10D, in some embodiments, determining an etch endpoint includesdetecting separation between the emission face of the fiber, now reducedto a point, and the emission face mask 1022. As an example, a machinevision system could monitor the emission face mask and provide anendpoint detection functionality.

It should be appreciated that the specific steps illustrated in FIG. 9provide a particular method of fabricating a shaped fiber using an etchprocess according to an embodiment of the present invention. Othersequences of steps may also be performed according to alternativeembodiments. For example, alternative embodiments of the presentinvention may perform the steps outlined above in a different order.Moreover, the individual steps illustrated in FIG. 9 may includemultiple sub-steps that may be performed in various sequences asappropriate to the individual step. Furthermore, additional steps may beadded or removed depending on the particular applications. One ofordinary skill in the art would recognize many variations,modifications, and alternatives.

In various embodiments, the mask dimensions and materials enablevariation in etch profiles to create many endpoint shapes. As anexample, depending on the etch chemistry, etchant can wick in betweenthe emission face and the emission face mask to form a convex lens onthe end of the fiber. Moreover, although the example illustrated inFIGS. 10A-10D are rotationally symmetric, the present invention is notlimited to this example and other mask shapes, for example apertures onopposing sides, can be used to enable the creation of cylindrical lenselements. Moreover, discrete apertures of various sizes, orientations,and the like can be utilized, providing ports for etchant inflow thatcan form profiles of arbitrary shape. One of ordinary skill in the artwould recognize many variations, modifications, and alternatives.

In addition to the process illustrated in relation to FIGS. 10A-10D,multi-step processes are included within the scope of the presentinvention. As an example, a first set of one or more etch resistantmasks could be applied, a first etching process could be performed, andsubsequent mask(s) could be applied followed by subsequent etchingprocesses.

Accordingly, multiple etch processes, each used to create different etchprofiles, can be combined to fabricate profiles of the desired shape.Thus, various combinations of successive masking and etching processesare included within the scope of the present invention. As anotherexample, a first masking design could be utilized to produce a firstshaped profile at the end of the fiber. A second, different emissionface mask could then be applied at a different orientation to etch analternative shape at the end of the fiber. Using photolithographicprocesses, high levels of control can be applied to the masks, enablinghigh levels of control for the etch profiles. As an example, althoughthe emission face mask 1020 has a diameter larger than the emissionface, thereby covering the entire face, this is not required anddifferent emission face masks, some covering the entire face and othersonly covering a portion of the face can be utilized in single step ormulti-step etching processes. Moreover, the thicknesses of the masks aswell their coverage areas are controllable according to embodiments ofthe present invention.

In some embodiments, rather than masking the end of the fiber, the sidescan be masked with a jacket and the end exposed to allow wicking of theetchant under the jacket to form a shaped tip on the fiber. The shapedtip can be formed as a conical structure, a hexagonal lens, or the like.

FIG. 10E is a simplified perspective view illustrating a fiber with aprotective cover according to an embodiment of the present invention. Aswill be evident to one of skill in the art, the waveguiding propertiesof optical fibers results from the different index of refractionassociated with the different materials utilized for the core andcladding of the fiber. As an example, for a fiber with a cladding offused silica and a doped fused silica core, thereby providing adifferent refractive index, the core/clad interface is susceptible toingress by the etchant (e.g., an HF-based etchant) and the etchant canwick along either the interface or into the core and preferentially etchthe core. Additionally, etch rates for the core and the clad may bedifferent, so the core may etch more quickly than the cladding.

Accordingly, embodiments of the present invention protect the core witha protective cover to prevent this core etching. The protective covercan cover the entire end or only a portion of the end. Referring to FIG.10E, the fiber 1050 includes core 1052. Protective cover 1054 is formedon the end of the fiber to protect the core from preferential etchingduring etch processing.

FIGS. 11A-11C are simplified side views illustrating a method offabricating a shaped fiber tip according to an embodiment of the presentinvention. As described in relation to FIGS. 11A-11C, the meniscusforming characteristics of the interface between the etchant and theinert layer, discussed above in relation to FIG. 6B, can be utilized toform a lens on the tip of the fiber. Referring to FIGS. 11A-11C, amethod of fabricating a lens on an optical fiber tip is provided. Themethod includes providing a fiber optic cable 1100 having an emissionregion 1110 and an emission face 1112. An etch solution 1120 having asurface 1122 is provided and the emission face is positioned to makecontact with the surface 1122 of the etch solution as illustrated inFIG. 11A. In the embodiment illustrated in FIG. 11A, the emission facedoes not extend below the surface 1122 and the hydrophiliccharacteristic of the fiber results in wicking of etchant up the side ofthe fiber, but in other embodiments, the fiber is positioned such thatthe emission face does extend below the surface.

Due to the wicking of the etch solution up the sides of the fiber, ameniscus 1130 is formed by the etch solution surrounding the emissionregion 1110. The meniscus 1130 is characterized by a greater width (w₁)adjacent the emission face 1112 than the width (w₂) at positions fartherfrom the emission face. The meniscus can also be characterized by aninitial height (H).

The presence of the etchant solution in the meniscus will result inetching of the emission region to form an initial etch profile 1140 asillustrated in FIG. 11B. The greater amount of etchant present adjacentthe emission face will result in a higher etching rate adjacent theemission face, with lower etching rates at the top of the meniscus.Accordingly, the etching process will remove more material adjacent thefiber/etchant interface, resulting in the initial etch profile 1140illustrated in FIG. 11B in which a convex feature is formed.

Because of the formation of the initial etch profile, the surfacetension changes produce a subsequent meniscus that is decreased inheight (H₂) to a value less than the initial height (H₁). As themeniscus height decreases, the etching process will continue to formsubsequent etch profiles 1150 as illustrated in FIG. 11C. As the etchantwicks up the sides of the fiber to a lesser extent, thereby varying theetch rate as a function of meniscus height, the etch process will form acurved lens on the fiber tip. In some implementations, the processillustrated in FIGS. 11A-11C will be a self-limiting process as meniscusdecreases in height until the emission face no longer makes contact withthe surface of the etchant. As a result, the method and system describedin relation to FIGS. 11A-11C provides reproducibility since the heightof the meniscus changes as the etch proceeds in a self-limiting manner.

In addition to formation of lensed fiber tips, the method illustrated inrelation to FIGS. 11A-11C can also be applied to other etching processesdiscussed herein to form desired profiles by control of the fiberposition adjacent the etchant. Moreover, embodiments of the presentinvention include methods and systems in which a first fiber shapingprocess is utilized to form a lens on the fiber tip, an etch resistantmask is used to protect the fabricated tip, and one or more subsequentfiber shaping processes are utilized to form other regions of the shapedfiber, for example, the tapered delivery region, the flexure region, orthe like. As will be evident to one of skill in the art, the order couldbe reversed. An advantage of processing the tip first will be theuniformity and size of the fiber during initial processing. An advantageof processing the tip last will be the ability to protect the tip untilit is processed, which can involve more delicate processing steps.Depending on the particular application, one or more of these advantagesmay be available. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

FIG. 12 is a simplified schematic diagram illustrating a waveguidefabrication system 1200 according to an embodiment of the presentinvention. As illustrated in FIG. 12, an etch system 1210 is providedthat can work in conjunction with robot 1212, cleaning system 1214,masking formation system 1216, and mask removal system 1218. Systemcontrol is provided by computer 1220, which can include one or moreprocessors, memory, and an input/output interface operable tocommunicate with the other illustrated systems. The etch system 1210 canbe a multi-tank system utilizing different etchant solutions asappropriate to the particular materials that are to be etched. Forexample, a first tank could include an HF-based etchant to etch glassand a second tank could include an H₂SO₄-based etchant to etch maskmaterials in conjunction with or in place of the mask removal system1218. Sealed tanks in the form of chambers can also be used. Thecleaning system 1214 can be integrated with the mask removal system 1218in some embodiments and can be used to clean the optical elements andprepare them for additional processing or after processing. As will beevident to one of skill in the art, the various systems illustrated inFIG. 12 can be combined into compound system elements including one ormore of the systems illustrated in FIG. 12.

Fiber optic cables or other suitable waveguide structures provided ininput/output stack 1222 can be picked up by robot 1212, partially maskedusing mask formation system 1216, and then a portion of the waveguidestructures can be etched using etch system 1210. Tapered profiles can befabricated as discussed herein. After the etching process, the cleaningsystem 1214 and/or the mask removal system 1218 (for example, using asulfuric acid bath) can be utilized to remove the mask and prepare thewaveguide structure for further processing.

Using the robot to translate the waveguide structure between the varioussystems under control of the computer 1220, different portions or thesame portions of the waveguide structure can be masked and etched, withthe processes repeating until the desired structure is fabricated. Uponcompletion of the fabrication process, the completed structure can bemoved to the output section of the input/output stack 1222 for futureuse, including packaging as an element of a motion actuation system.

It is also understood that the examples and embodiments described hereinare for illustrative purposes only and that various modifications orchanges in light thereof will be suggested to persons skilled in the artand are to be included within the spirit and purview of this applicationand scope of the appended claims.

What is claimed is:
 1. A fiber optic element of a fiber scanning system,the fiber optic element comprising: a fiber optic cable having: an inputregion; a support region coupled to the input region; and a lightemission tip, wherein the support region is characterized by a firstdiameter and the light emission tip is characterized by a seconddiameter less than the first diameter, wherein the input region islocated further from the light emission tip than the support region; anda motion actuator having: longitudinal side members; an internal orificedisposed between the longitudinal side members; a first region disposedat one end of the motion actuator; a central region; and a second regiondisposed at an opposing end of the motion actuator; wherein the supportregion of the fiber optic cable is disposed in the second region of themotion actuator, wherein the input region of the fiber optic cable isdisposed within the longitudinal side members and separated from thelongitudinal side members by a flexure distance.
 2. The fiber opticelement of claim 1 wherein the fiber optic cable tapers from the supportregion to the light emission tip.
 3. The fiber optic element of claim 1wherein the input region is disposed in the central region of the motionactuator.
 4. The fiber optic element of claim 1 wherein the supportregion of the fiber optic cable is in mechanical contact with secondregion of the motion actuator.
 5. The fiber optic element of claim 1wherein: the fiber optic cable further comprises a second support regioncoupled to the input region; and the second support region is disposedbetween the first region of the motion actuator.
 6. The fiber opticelement of claim 5 wherein: the support region of the fiber optic cableis in mechanical contact with second region of the motion actuator; andthe second support region of the fiber optic cable is in mechanicalcontact with the first region of the motion actuator.
 7. The fiber opticelement of claim 5 wherein the input region is characterized by a thirddiameter less than the first diameter, and the second support region ischaracterized by a fourth diameter greater than the third diameter. 8.The fiber optic element of claim 5 wherein the second support region ischaracterized by the first diameter.
 9. The fiber optic element of claim1 wherein: the motion actuator comprises a piezoelectric actuator; andthe longitudinal side members comprises a first piezoelectric elementoperable to contract/expand and a second piezoelectric element operableto expand/contract in opposition to the first piezoelectric element. 10.The fiber optic element of claim 1 wherein the internal orifice of themotion actuator is characterized by a cylindrical profile defined by aninternal diameter and the support region is characterized by an outsidediameter substantially equal to the internal diameter.
 11. The fiberoptic element of claim 10 wherein: the fiber optic cable furthercomprises a second support region coupled to the input region; thesecond support region is disposed between the first region of the motionactuator; and the second support region is characterized by an outsidediameter substantially equal to the internal diameter.
 12. The fiberoptic element of claim 1 wherein the input region is characterized by athird diameter less than the first diameter.
 13. The fiber optic elementof claim 1 wherein the input region is disposed in the first region ofthe motion actuator.